Western Digital Elements 500GB External drive - £69.99 delivered @ Amazon !
Cheapest price at the moment.
Manufacturer's Description : The Elements USB 2.0 external hard drive is a fast, easy, reliable way to add more storage to your PC or Macintosh. Simply plug it in to a USB port and start saving or backing up your photos, music video and files. It's pre-formatted for immediate use. The compact, durable metal case provides extra data protection.